Depth gauge



FIG. 1 is a perspective view of a depth gauge, showing my new design;

FIG. 2 is a left side elevation view thereof, the right side elevation view being a mirror image thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a rear elevation view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof. 

The ornamental design for a depth gauge, as shown and described. 